The inventive concept relates to a light-emitting device including an omnidirectional reflector in which two nitride-based semiconductor layers having different refractive indices are alternately formed.
A light-emitting device chip, for example, a light-emitting diode (LED), refers to a semiconductor device that displays multi-color light by forming a light-emitting source through a PN junction between compound semiconductors. An LED has advantages of a long lifetime, small and light design, and low energy consumption due to good light directivity. Also, since an LED is durable against impact and vibration, the LED does not require a pre-heating time and a complex operation, and may be packaged in various forms. These permit the LED to be used for various applications.
When a GaN LED is grown on a heterogeneous substrate, in order to effectively extract light in one direction, a reflector is disposed in a direction opposite to a direction to which a light-emitting unit extracts light. When a reflector formed of a metal material is deposited, it is difficult to have a reflectance of about 100% by using only the reflector. When materials having different refractive indices are alternately deposited, it is difficult to grow a high quality light-emitting unit due to mismatch between the materials and the light-emitting unit that is deposited on the materials. Also. since a multi-layer structure is required due to a small refractive index difference between adjacent layers, a time taken to manufacture a reflector is increased.